The 'Dance Again' singer and the 'Tonight Show' host dance in their tight pants that they are very proud of but later cause an argument between them.

Jennifer Lopez and Jimmy Fallon had a groovy dance-off when the former stopped by "The Tonight Show" on Monday, June 9. The show's host started it out solo, sporting a wig, a blue-striped shirt and white pants while he sang and bragged about his tight pants.

J.Lo showed up after Fallon finished his rendition about his favorite pants. Rocking a similar wig and tight pants paired with a crop top, she also sang about the tight pants that she's very proud of.

The two soon had an argument about whose pants were the tightest in town, with each other claiming that their own pants became the talk of the town. "Listen up, you little b***h!" the "I Luh Ya Papi" songstress shouted at Fallon, "You better hide your wife, you better hide your kids, because I will cut you. I will cut your father, I will cut your mother. I will scratch you. Don't make me take off my heels!"

She managed to scare Fallon, forcing him to leave the stage and find a new town.